Ingot mold and hot top therefor

ABSTRACT

A combined ingot mold and hot top for use in the casting of ingots from molten steel. The top surface of the mold is provided with an upwardly projecting, rounded ridge immediately adjacent to the cavity walls. The hot top is composed of a single piece of reinforced insulating matrial and has a concave groove on its lower surface which mates with the projecting ridge of the mold. Various means are provide to clamp the hot top to the mold to prevent the same from floating.

United States Patent 91 Nadrich et a1. v

m1 3,794,262 14 1' Feb. 26, 1974 1 INGOT MOLD AND HOT TOP THEREFOR [76] Inventors: John Nadrich, 9756 South Ave.,

Ext, Youngstown, Ohio 44514; John A. Ericson, 732 Market St., Youngstown, Ohio 44502 221 Filed: Sept. 20,1971

[21] Appl. No.: 182,207

Related us Application Data [63] Continuation of Ser. No. 28,044, April 13, 1970,

which is a continuation-in-part of Ser. No. 704,459,

Feb. 9, 1968, abandoned.

52 US. Cl 249/106, 249/202 51 161. ci B22d 7/10 [58] Field of Search 249/106, 197-202 [56] References Cited UNITED STATES PATENTS Howard et al. 249/106 1/1924 Howard et al. 249/197 2/1936 Charman 249/202 UX Primary Examiner-Robert D. Baldwin Attorney, Agent, or FirmOldham & Oldham Co.

[ 5 7] ABSTRACT A combined ingot mold and hot top for use in the casting of ingots from molten steel. The top surface of the mold is provided with an upwardly projecting, rounded ridge immediately adjacent to the cavity walls. The hot top iscomposed of a single piece of reinforced insulating matrial and has a concave groove on its lowersurface which mates with the projecting ridge of the mold. Various means are provide to clamp the hot topto the mold to prevent the same from floating.

4 Claims, 4 Drawing Figures PATENTEB W 3,794,262

JOHN 1 YJOHN A. ERICSON B fax X/W AGENT INVENTORS NADR ICH 1 This is a continuation of application Ser. No. 28,044, I

filed Apr. 13, I970 now abandoned, which'is a continuation-in-part of application Ser. No. 704,459, filed Feb. 9, 1968, now abandoned.

This invention relates to ingot molds such as are used in the steel industry in the casting ofingots from molten steel from open-hearth furnaces and the like and more particularly to an improved ingot mold and hot top combination. v

In order to prevent the formation of a cavity or pipe extending from the'up'per surface of the ingot downwardly towards its center, it iscommon practice, especially where ingots are being cast of high quality steel, to provide an additional volume of molten steel above the level of the ingot. This additional volume provides a reservoir of molten steel which flows into the mold cavity as the steel therein solidifys and contracts. In order to keep this additional volume of steel in a hot, molten state, an open-ended insulating. or exothermic container or hot top is positioned on the top of the mold, extending the mold cavity upward.

For efficient, economical ingot casting, it is important that the hot tops be capable of rapid assembly and reliable performance. It is also desirable that the hot top seal securely with the mold sothat there is no leakage of molten steel between the hot top and themold.

Presently employed hot tops either consist of numerous parts whichrequire a substantial amount of time for assembly and which, because of the numerous parts, are susceptable to misalignment and malfu nction, or'are of great weight and thus difficult tohandle. Also, presently employedhot tops do not provide an adequate seal between the hot top and the mold and it is therefore necessary to interrupt the flow of molten steel when the level of the same reaches the lower edge of the hot top to permit the hot top to be frozen to the mold. This arrangement results in inferior quality of ingotsas the molten steel added to the ladle after the interruptiondoes not always bond adequately to the steel w-hich was previously in the ladle. This arrangement also results in the shortening' of the effective life of the controls of the teaming ladle as these controls must be subjected to much'more frequent use. lr i the event it becomes impossible to stop "the flow of molten steel into the ingot, the present hot tops are. totally ineffective as it is not possible to seal them securely to the mold and the excess volume of molten steel is thus lost.

It is the primary object of the present invention to provide an improved ingot mold and hot top which may be rapidly assembled and which eliminates the neces- 'sity of interrupting the flow of molten steel into the mold. It is a further object of ourinvention to provide an improved hot top and mold combination which may be assembled with a greatly reduced possibility of er- I'OI'.

As will be more apparent from the following description of a preferred embodiment of the invention, an effective seal between the mold and hot topis achieved by the provision of an upwardly-projecting ridge atthe upper end of the'mold which is tapered on its side portions and rounded at i ts upper end and a complimentary groove in the lower surface of the hot top.

The-above and other Objects and advantages of our invention will become apparent upon consideration of the following specification and i the accompanying drawing wherein there is shown a preferred embodiment of our invention;

' In the drawing:

FIG. I is a side elevational view of the mold and hot top of our invention, partially in section;

FIG. 2 is a plan view of the mold and hot top of FIG. I, with a portion of the hot top broken away to show the top surface of the mold;

FIG. 3 is a fragmentary side elevational view, in section, showing a modified arrangement for securing the hot top'to the mold; and,

FIG. 4 is a fragmentary side elevational view, in section, showing a further modification of our invention.

Reference numeral 10 designates generally an ingot mold, preferably of the solid bottom type, The mold has a cavity 11 extending downwardly from the top of the mold, tapered sidewalls 12, and lugs 13 and 14 which are employed in 'moving and-stripping the mold.

described'nThe hot top l6'has an opening extending downwardly through its center. The inner side walls of the hot top may beeither straight or slanted as shown in the drawings. The hot top may also be provided with a skirt portion 20 which projects downwardly into the mold cavity 11 and with a'pair of projecting lugs 21 to facilitate the removal of the cast ingot from the mold.

The rounded upper end or ridge 15 of them old I9 is of a height at least equal to approximately one-half the thickness of the base of the ridge l5 and is rounded at its upper end. The radius of the upper end is within a range of approximately one-twelth to one-half the thickness of the base of the ridge. It should be noted 7 that-the center of curvature of the rounded upper end of the ridge 15 is not necessarily vertically aligned with the midpoint of the base. A typical ridge is one having a base thickness of5 and Al inches, a height of 3 inches, and aradius ofcurvature of the upper end of 1 inch with the center of curvature offset from thecenter of thebase by five-eighths inch towards the center of the mold. The groove 18 of the hot top is of complimentary shape but, .preferrably, of a lesser depth than the heighth of the ridge so that theentire weight of the hot top is borne by-the ridge 15.- t

This arrangement of a ridge l5 at the upper end of the ingot mold -I0 1and a complimentary groove 18 in the lower surface of the hot top 16 assures an effective seal since the wedging action between the ridge 15 and groove 18 results in tight-fitting engagement between the mold and hot top; This seal is achieved even when the corresponding dimensions of the ridge and groove differ somewhat from one another. Thus, if the groove 18 of the hot top 16 is slightly oversize, the hot top will rest lower on the ridge 15 and a seal will be achieved near the top of the groove. lf.'on the other hand, the groove 18 is tindersizethe seal will be effected near the lower end of the groove. a

Under some circumstances. the weight of the hot top and the'configuration of the ridge and groove will be sufficient to assure a complete" sealing between the mold and hot top and will prevent the hot top from floating when filled with molten steel. However, a lightweight hot top may tend to float, destroying the seal. In such cases a clamping arrangement may be provide to secure the hot top to the mold. One clamping arrangement is shown in FIG. 1 where a steel bar 22 is welded to the reinforcing framework 17 and projects outwardly through the side of the hot top. One end of a clamp indicated schematically at 23 in FIG. 1 engages the projecting bar 22 while the opposite end of the clamp engages in a groove 24 in the outer surface of the mold wall 12. This clamp 23 is preferably of the toggle type to permit the mold and hot top to be rapidly clamped together without the need for adjustment of the clamp. It will be understood that, preferably, a clamp is provided on each of the four sides of the hot top. While the notches 24 are shown as extending along only a portion of the upper rounded portion 15 of the mold walls, it will be understood that this notch may be in the form ofa continuous groove extending around the outer surface of the mold walls 12.

When the hot top 16 is positioned on the mold l and the clamps 23, if provided, are drawn tight, the groove 18 in the lower surface of the hot top'and the rounded upper portion of the mold walls 12 are drawn tightly together forming an effective seal between the mold and the hot top. When the level of molten steel-in the ladle has reached the level of the hot top, any molten steel which has entered the interstice between the skirt 20 of the hot top and the mold walls 12 will be blocked by the seal formed between the groove 18 and the rounded portion 15 of the mold wall and thus the hot top may be filled without the fear of losing any of the molten steel therein. The clamps 23, in addition to asgroove 18 which mateswith the upper surface of the ridge 15' and clamping means 22, 23, and 24' similiar to the clamping means shown in FIG. 1 may be used to secure the hot top to the mold. Also aplurality of vertically disposed circumferential grooves 29 may be provided in the outer portion of the skirt 20 of the hot top to further restrict the pressure applied by the molten steel to the sealingarea 15, 18" between the mold and hot top.

It will be readily apparent that changes may be made in and to the illustrated embodiments of our invention.

In particular, the various clamping means shown and between the mold and hot top, a sealing mixture such as a mixture of fine silicon sand,powdered alumina, and sodium or potassium silicate may be applied to the groove 18 before assembly. Such amixture will become somewhat elastic upon heating by the molten metal in the mold and hot top and will effectively seal any irregularities between the ridge l5 and groove 18 thus assuring an adequate seal between the mold and hot top.

It will now be apparent that we have invented a new moldand hot top combination wherein there'is pr'o-- vided an effective seal between the mold and the hot suring the tight seal between the mold and hot top, also effectively restrain the hot top from floating. It should also be noted that the portion of the hot top which forms the seal is protected by the downwardly projecting skirt 20 and the outer edge 25 ofthe hot top so that the sealing surface 18 is notlikely to become damaged even if the edges of the hot top are chipped or cracked during shipping, handling, and the like.

The embodiment of our invention shown in FIG. 3 illustrates another method of securing the hot top to the mold. Secured to the reinforcing framework 17' of the hot top 16' is an outwardly projecting and downwardly projecting bar or rod 26. Lugs 21 having verically extending holes therethrough are provided on the outer surfaces of the mold walls 12. The downwardly projecting end of the bar or rod 26 is passed through the hole in lug 27 and may be secured by wedges, not,

shown herein, passing through elongated openings 28 in the lower end of the bar or rod '26. It will be readily apparent that the opening 28 may be omitted and the lower end of the rod 26 threaded. In this modification outer portion of the upper surface of the mold is flat as indicated at 15". The hot top 16" is provided with a top thus eliminating the necessity of interrupting the flow of molten steel into the mold when casting ingots.

It will also be apparent that the combination herein disclosed is of simple construction and may be rapidly and accurately assembled. As changes may be made in and to the embodiments illustrated reference should be had to the appended claims in determining the true scope of our invention. I

We claim: I

1. A hot top and ingot mold combination where the ingot mold has an upwardly projecting ridge at its upper end, the ridge surrounding the mold cavity and being of a height of not less thanapproximately onehalf the thickness of the ridge at the base thereofthe ridge having a side portion extending upwardly and outwardly from the mold cavity wall in a smooth transition from the cavity wall and extending at a small acute angle from the vertical, the upper end of the ridge being rounded on a radius of curvature of from onetwelfth to one-half the thickness of the base and including a unitary hot top having a groove in its lower surface complementary to the upwardly projecting ridge ofthe mold for'receiving the. ridge'of themold, said groove including an inclined surface peripherally engaging the inner face of the ridge in a wedging action resulting in a tight fitting sealing relationship.

2. A hot top according to claim '1 wherein thedepth of said groove is less than the height of said ridge.

3. An ingot mold and hot top combination, comprising an ingot mold having an upwardly projecting ridge at its upper end, the ridge surrounding the mold cavity and being of a height of not less than approximately one-half the thickness of the base thereof, the ridge having an inner side portionextending upwardly and outwardly from the mold cavity wall in a smooth transition from the cavity wall and extending at a small acute angle from the vertical, the upper end of the ridge being rounded; a unitary hot top having a complementary shaped groove in its lower surface for receiving the ridge of the mold, said groove including an inclined surface on a laterally inner portion thereof peripherally engaging the inner face of the ridge in a wedging action resulting in a tight fitting sealing relationship therebetween; and 

1. A hot top and ingot mold combination where the ingot mold has an upwardly projecting ridge at its upper end, the ridge surrounding the mold cavity and being of a height of not less than approximately one-half the thickness of the ridge at the base thereof, the ridge having a side portion extending upwardly and outwardly from the mold cavity wall in a smooth transition from the cavity wall and extending at a small acute angle from the vertical, the upper end of the ridge being rounded on a radius of curvature of from one-twelfth to one-half the thickness of the base and including a unitary hot top having a groove in its lower surface complementary to the upwardly projecting ridge of the mold for receiving the ridge of the mold, said groove including an inclined surface peripherally engaging the inner face of the ridge in a wedging action resulting in a tight fitting sealing relationship.
 2. A hot top according to claim 1 wherein the depth of said groove is less than the height of said ridge.
 3. An ingot mold and hot top combination, comprising an ingot mold having an upwardly projecting ridge at its upper end, the ridge surrounding the mold cavity and being of a height of not less than approximately one-half the thickness of the base thereof, the ridge having an inner side portion extending upwardly and outwardly from the mold cavity wall in a smooth transition from the cavity wall and extending at a small acute angle from the vertical, the upper end of the ridge being rounded; a unitary hot top having a complementary shaped groove in its lower surface for receiving the ridge of the mold, said groove including an inclined surface on a laterally inner portion thereof peripherally engaging the inner face of the ridge in a wedging action resulting in a tight fitting sealing relationship therebetween; and clamping means to releasably secure said hot top to said mold.
 4. An ingot mold and hot top combination as in claim 3 where a skirt portion is provided on the hot top on the laterally inner portion thereof, the skirt terminating at a point below the laterally outer lower edge of the hot top. 